DNA tests have tied at least six sexual attacks in Queens and The Bronx to the same man, police said yesterday.

The victims ranged in age from a 9-year-old Jackson Heights girl who was sodomized in her apartment to a 26-year-old Bronx woman who was raped.

Authorities said the suspect gained access to the victims’ apartments by following them in or by knocking on the doors and claiming he was there to fix a water leak.

Deputy Chief Joseph Reznick of Queens detectives warned residents to beware the leak story, “one of the dozens of ruses that people use to gain entry into an apartment.”

“If in doubt, keep them out,” Reznick said.

The incidents stretched from March 1997 to last Sept. 25. Detectives are checking to see if other assaults fit the pattern. In some cases, the suspect held his victims at knifepoint. In others, he choked them until they were unconscious.

Police said anyone with information should call (800) 577-TIPS. Calls are confidential. There is a $2,000 reward for information leading to the suspect’s arrest.